Matrix guide



Sept. 11, 1945. G. J. KOCH ETAL MATRIX GUIDE Filed July 8, 1944 GEORGEJ. KOCH ROGER P. LEAVITT INVENTORS Wflfiw BY ATT'Y & AG'T N m A L m :3 16 2 KM, 5 /1 4 Z Z FL 2 2 G H x Patented Sept. 11, 1945 UNITED STATESPATENT OFFICE MATRIX GUIDE Application July 8, 1944, Serial No. 544,0787 4 Claims.

This invention relates to printing devices particularly to pressureapplying mechanisms for use in processes in which printing ink or othermedium is transferred from two matrices simultaneously to opp site sidesof a sheet.

Such processes include vectographic printing in which'the vectosensitivematerial receives the appropriate ink from flexible wash of! reliefmatrices between which it is sandwiched. It is the object of theinvention to provide a suitable guiding device so that the sheet to beprinted, such as the vectosensitive material, can be fed between thematrices to make contact therewith only as the sandwich reaches thepoint at which pressure is applied or at least just before it reachesthis point It furthermore is the object of the device to prevent theinked up matrices from touching the sheet material at any time prior tothe desired contact and thus to insure accurate and precise printing.

It is an object of one embodiment of the invention to provide means forholding the upper matrix out of the way, without marring this-matrix andwithout applying any harmful degree of tension thereto.

It is an object of one embodiment of the invention to provide convenientclamp means for holding the two matrices in register so that asuccession of prints may be made therefrom without incurring thepossibility of lack of register between the images on the two sides ofthe sheet. With such an arrangement, a preferred embodiment of theinvention has the guide mechanism so arranged that it may be quicklymoved to one side while the matrices are arranged to receive the sheetsto be printed.

According to the present invention the above advantages are gained in aduplex printing device by having a pair of pressure rollers resilientlyurged toward each other and with some driving means so that the wholedevice may be used for sandwiching the sheet between the printingmatrices. A table is provided for supporting the lower matrix as thelead edge of the sandwich is fed between the rollers and means areprovided for holding the upper matrix out of contact with the lower oneexcept just before they reach the pressure rollers. Between the twomatrices there are located two guides at fixed separation between whichthe sheet to be printed is loosely fed and the lead edge of the sheetengages the two matrices to form the sandwich just as it reaches thepressure rollers. These guides insure against contact between the sheetand either matrix prior to the formation of the sandwich.

In a preferred embodiment of the invention a roller holding the uppermatrix lightly against the upper one of the pressure rollers constitutespart of the means for holding the matrices separated. The advantage ofthis feature is the fact that the upper matrix is fed by this pressureroller outward toward the rest of the sandwich forming system at exactlythe same speed as the sandwich as a whole is fed through the pressuresystem which insures that the loop or slack portion in the upper matrixremains constant throughout the printing cycle. Preferably the lowermatrix rests on a rigid plate and the lead edge of the matrix sandwichis secured to this plate by a clamping bar which passes, during theprinting cycle, between the pressure rollers pulling both matrices, andbetween the matrices the printing sheet, with it. The matrices can beinked up without being removed from this rigid plate which insuresmaintenance of registration of the matrices from one print to the nextand then the matrices can be quickly mounted in position to receive theprint sheet. To render this operation even more convenient, the printsheet guides are hingedly arranged on the apparatus so that they may beswung to one side while the matrices are placed in position and thenbrought back between the matrices to guide the print sheet during theprinting cycle.

The invention will be fully understood from the following descriptionwhen read in connection with the accompanying drawing in which:

Fig. 1 is a perspective view of the preferred embodiment of theinvention.

Fig. 2 is a side elevation partly in cross section of the arrangementshown in Fi 1.

In Fig. 1 two printing matrices l0 and ii are clamped to a steel plate Hby a clamping bar l3. The edge provided by the clamping bar l3constitutes the lead edge of the matrix sandwich which is to be fedbetween pressure rollers I1 and I8 resiliently urged toward each otherby springs in the usual way but not shown, the pressure being adjustedby means of hand screws IS. The edge of the clamp bar I3 is beveled soas to pass easily between the pressure rollers I! and I8. Rotation ofthe rollers is provided by a handle l9 and suitable gears which may beof the usual type but which are preferably arranged as described in thecopending application Serial No. 544,077 of one of us (Leavitt) filedJuly 8, 1944, concurrently herewith.

As the matrix sandwich is fed to the pressure rollers, the plate I2 andthe lower matrix 10 are supported by a table H. The upper matrix H isfolded back over the roller I1 and held in contact therewith by a wheel20 lying lightLv thereon, the pressure supplied by a spring 2| beingjust suflicient to hold the matrix II firmly against the rolls" I'lwithout damaging the matrix in any way. am. the matrices Ill and II havebeen inked up they are placed in the position shown in Figs. 1 and 2, ahandle 22 being provided for raising the roller wheel 20 while thematrix II is brought into place. It will be noticed that as the matrixsandwich is fed between the rollers I1 and I8, the rotation of theroller I'l simultaneously feeds the upper matrix I I past the roller 20at the same speed as this matrix II is passed between the rollers I1 andIt so that the loop formed by the matrix I l stays the same size.

While the inked up matrices are being thus arranged, guides 25 and 26for the print sheet are positioned to one side, as shown by broken lines30 in Fig. l. The guides 25 and 26 carried by end pieces 21 and 29 arethen turned on hinge 28 to the position shown in both Figs. 1 and 2. Thesheet 24 to be printed is then fed loosely between the guides 25 and 28which are at fixed separation so as not to bear on the print sheet 24 oron either matrix III or II. The guides 25 prevent the sheet 24 and thelower matrix I coming into contact and the guide prevents the loop ofthe upper matrix II from touching the print sheet 24. This wholearrangement insures that the matrices I0 and l I engagethe print sheet24 only immediately before the whole sandwich enters the pressure areaprovided by the pressure rollers I1 and I8.

Repeated operation of this mechanism is quite convenient and yet theabsolute registration between the images provided by the matrices I land I I is not disturbed.

Having thus described the preferred features of our invention we wish topoint out that it is limited in scope only by the following claims.

What we claim is:

l. A duplex printing device for use in a process in which printingmedium is tranferred to both sides of a sheet simultaneously from twoflexible matrices fastened together at the lead edge, comprising a pairof pressure rollers resiliently urged toward each other, means fordriving the rollers in opposite directions for sandwiching the sheetbetween the matrices, a table to support the lower matrix as the leadedge is fed between the rollers. means for holding the upper matrix outor contact with the lower one except as they reach the pressure rollersand two guides above the table and at fixed separation between whichsaid sheet is loosely fed to the matrix sandwich for insuring a ainstcontact between the sheet and either matrix prior to reaching thepressure rollers.

2. A device according to claim 1 in which the means for holding theupper matrix is a rolling member lightly urging the upper matrix towardthe upper one of the two pressure rollers whereby the upper matrix isfed to the sandwich at approximately the same speed as the sandwich isfed between the rollers.

3. A device according to claim 1 in which a rigid plate is included onthe table including clamping means for the lead edge and forming part ofthe sandwich which passes between the pressure rollers.

4. A device according to claim 1 in which the two guides are hingedlymounted on the table to be swung to one side as the matrices are set inplace and to be swung between the matrices to be in place to guide thesheet being printed.

GEORGE J. KOCH. ROGER P. LEAVITT.

